I have been researching myself to try and find any causal links between soy ingestion and my negative flare ups. This is what I have found out so far in a nutshell.It is known that FQ’s damage affects the neurotransmitters in the body. There is some debate on the level of damage done to each. For instance it is known that FQ’s definitely damages the GABA system. I do not know to what level it damages the acetylcholine (ach) neurotransmission system but according to most symptoms that floxies have the ach system seems to have damage. The ach system is excitory and according to the flox report if the ach system is damaged excessive ach would build up around the nerves and then it would cause insomnia, tense muscles, irritability, depression, headache and restlessness.
Basically soy contains acetylcholine (a google search will result in all kinds of reports on soy and ach). If the average person ingests soy it does not usually effect them but in someone whose ach system is damaged it could cause the above symptoms and maybe more. So basically you could get tested for soy sensitivity and it will probably come back normal, since it is not actually the soy your are allergic to or sensitive to but the effects is has on the ach system.